Thanks to the invaluable assistance of JJ109 and Greyfox, I'm seeing the light at the end of the tunnel. Just a final clarification for these two, please!
ACROSS:
13 Captivated European by force almost (5) : EPRI? ( EPRIS )?
( Trying to see how this fits in the preamble...)
26 I’d back player of old instrument? I’m weakening (7): DI?U?ER ( DILUTER ) ?